As well known to those skilled in the art, various types of taps used for controlling the flow of liquid such as water, oil, or gas are proposed and widely used. Such taps are individually provided with a valve for selectively opening or closing the liquid passage in a tap. However, such a known tap is not provided with any means for automatically opening or closing the valve and so the valve has to be manually operated and is inconvenient to users. In addition, such a known tap allows a user to lose a considerable amount of liquid regardless of how carefully the user handles the tap, thus overly consuming the liquid. In each of the known taps, the vertical position of a liquid outlet port is fixed. Therefore, such a known tap fails to allow a user to move the vertical position of the outlet port when necessary. Another problem of such taps resides in that they individually have a connector, which is produced separately from a tap body and is attached to the tap body for the purpose of connecting a hose or a rotatable joint for the purpose of connecting a hose or a rotatable joint to the tap body. Such connectors increase the number of parts of the taps and complicate the production process of the taps, thus increasing the manufacturing cost of the taps.